Changes of resting-state neural activity and nerve fibers in ischemic stroke patients with hemiplegia

Many neuroimaging studies have reported that stroke induces abnormal brain activities. Yet, little is known about resting-state networks (RSNs) and the corresponding white matter changes in stroke patients with hemiplegia. Here, we utilized functional magnetic resonance imaging (fMRI) to measure the neural activity and related fiber tracks in 14 ischemic stroke patients with hemiplegia and 12 healthy controls. The fractional amplitude of low-frequency fluctuations (fALFF) calculation and correlation analyses were used to assess the relationship between the regional neural activity and movement scores. Tractography was performed using the diffusion tensor imaging (DTI) data to analyze the fibers passing the regions of interest. Compared with controls, stroke patients showed abnormal functional connectivity (FC) in some brain regions of the RSNs. The fALFF was increased in the contralesional parietal lobe, with the regional fALFF being correlated to behavioral scores in stroke patients. And the tracked fibers across regions with reduced FC in the RSNs were increased in stroke patients. The study suggested that structural remodeling of functionally-relevant white matter tracts probably be an adaptive response that compensates for injury to the brain.